<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        .frist{
            height: 300px;
            display: flex;
            width: 100%;
            justify-content: space-evenly;/*间隔相等*/
            /*justify-content: space-between;左右两端对齐
            justify-content: flex-end;靠右对齐
            justify-content: space-around;容器之间的间距是两点间距的二倍
           justify-content: center;/*横轴居中*/
            
        }
        .box{
            width: 200px;
            height: 200px;
            background: rgb(107, 11, 114);
            border: 2px rgb(148, 36, 5) solid;
        }
        .second{
            width: 100%;
            height: 300px;
            display: flex;
            align-items:center;/*交叉轴居中*/
            /*align-items: center;
            justify-content:center;平垂直居中*/
            /*
            align-items: flex-end;交叉轴底部
            align-items: flex-start;/*默认*/
        }
        .third{
            width: 100%;
            height: 300px;
            display: flex;
            flex-direction: reverse;/*排序倒排*/
            /*flex-direction: row;默认排序
            flex-direction:column 按列排列 
            flex-direction:column-reverse 倒序
            */
        }
        .four{
            width: 100%;
            height: 300px;
            display: flex;
        }
        .boxs{
            width: 200px;
            height: 200px;
            background: rgb(15, 87, 107);
            border: 2px rgb(148, 36, 5) solid;
        }
        .boxs:nth-child(1){
            order: 2;
        }
        .boxs:nth-child(2){
            align-self:flex-end;
        }
        .boxs:nth-child(3){
            order: 0;
        }
        .fifth{
            width: 420px;
            height: 400px;
            display: flex;
            margin: auto 0;
           flex-grow: 0;
        }
   
    </style>
</head>
<body>
    <div class="frist">
    <div class="box">a</div>
    <div class="box">b</div>
    <div class="box">c</div>
    </div>
<div class="second">
    <div class="box">a</div>
    <div class="box">b</div>
    <div class="box">c</div>
</div>
<div class="third">
    <div class="box">a</div>
    <div class="box">b </div>
    <div class="box">c </div>
</div>
<div class="four">
    <div class="boxs">a</div>
    <div class="boxs">b</div>
    <div class="boxs">c</div>
    
</div>
<div class="fifth">
    <div class="box">a</div>
    <div class="box">b</div>
    <div class="box">c</div>
</div>
</body>
</html>